masterThesis
Development of a novel polycrystalline diamond composite using tantalum as a binder
Fecha
2021-06-28Registro en:
MEDEIROS, Regina Bertília Dantas de. Development of a novel polycrystalline diamond composite using tantalum as a binder. 2021. 99f. Dissertação (Mestrado em Ciência e Engenharia de Materiais) - Centro de Ciências Exatas e da Terra, Universidade Federal do Rio Grande do Norte, Natal, 2021.
Autor
Medeiros, Regina Bertília Dantas de
Resumen
Polycrystalline diamond (PCD) is widely applied in the cutting and drilling industries due
to its excellent mechanical properties. Currently, several researchers have been studying
the use of different binders in its manufacturing, seeking to improve their properties and
reduce the use of traditional metals that are harmful to human health and the environment.
This work aimed to study the applicability of tantalum as a novel binding agent of PCD.
The products developed here were processed using powder metallurgy and High
Pressure-High Temperature (HPHT) sintering. The effect of different tantalum
concentrations (2.5, 5.0, 7.5, and 10.0 wt. %) was investigated using X-ray diffraction
(XRD), Confocal Microscopy, Density measurement, Particle Size Analysis, and
Scanning Electron Microscopy (SEM). Mechanical properties and failure behavior were
employed to evaluate the products. The PCD-Ta system was also tribologically tested
against ferrous and ceramic materials, in order to simulate their applicability in industrial
machining conditions. The results suggest that increasing Ta quantity on PCD mixtures
promoted reduction of milling contaminations and enhanced the mechanical properties of
the as-sintered bodies by modifying the fracture mechanism predominance. No
occurrence of chemical reactions between the two compounds was observed on the
milling, but the formation of TaC resulting from a reaction between the free carbon and
the metallic Ta was identified on all as-sintered compositions. The PCD-Ta ratio directly
influences the tribological behavior of the present system with ceramic and ferrous
materials, and severest wear was provoked by samples with the lowest binder content.
Furthermore, abrasive and adhesive were the predominant wear mechanisms detected in
all studied compositions. Finally, the overall microstructural, mechanical, and
tribological outcomes demonstrated that the developed composites presented satisfactory
performance, which indicates that tantalum can be a viable alternative to act as a PCD
binder.